package com.rongzer.efapiao.util;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.io.IOUtils;

import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;
/**
 * Created by Administrator on 2018/3/14.
 */
public class RSAUtils {

    public static final String CHARSET = "UTF-8";
    public static final String RSA_ALGORITHM = "RSA";


    public static Map<String, String> createKeys(int keySize){
        //为RSA算法创建一个KeyPairGenerator对象
        KeyPairGenerator kpg;
        try{
            kpg = KeyPairGenerator.getInstance(RSA_ALGORITHM);
        }catch(NoSuchAlgorithmException e){
            throw new IllegalArgumentException("No such algorithm-->[" + RSA_ALGORITHM + "]");
        }

        //初始化KeyPairGenerator对象,密钥长度
        kpg.initialize(keySize);
        //生成密匙对
        KeyPair keyPair = kpg.generateKeyPair();
        //得到公钥
        Key publicKey = keyPair.getPublic();
        String publicKeyStr = Base64.encodeBase64URLSafeString(publicKey.getEncoded());
        //得到私钥
        Key privateKey = keyPair.getPrivate();
        String privateKeyStr = Base64.encodeBase64URLSafeString(privateKey.getEncoded());
        Map<String, String> keyPairMap = new HashMap<String, String>();
        keyPairMap.put("publicKey", publicKeyStr);
        keyPairMap.put("privateKey", privateKeyStr);

        return keyPairMap;
    }

    /**
     * 得到公钥
     * @param publicKey 密钥字符串（经过base64编码）
     * @throws Exception
     */
    public static RSAPublicKey getPublicKey(String publicKey) throws NoSuchAlgorithmException, InvalidKeySpecException {
        //通过X509编码的Key指令获得公钥对象
        KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(Base64.decodeBase64(publicKey));
        RSAPublicKey key = (RSAPublicKey) keyFactory.generatePublic(x509KeySpec);
        return key;
    }

    /**
     * 得到私钥
     * @param privateKey 密钥字符串（经过base64编码）
     * @throws Exception
     */
    public static RSAPrivateKey getPrivateKey(String privateKey) throws NoSuchAlgorithmException, InvalidKeySpecException {
        //通过PKCS#8编码的Key指令获得私钥对象
        KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(Base64.decodeBase64(privateKey));
        RSAPrivateKey key = (RSAPrivateKey) keyFactory.generatePrivate(pkcs8KeySpec);
        return key;
    }

    /**
     * 公钥加密
     * @param data
     * @param publicKey
     * @return
     */
    public static String publicEncrypt(String data, RSAPublicKey publicKey){
        try{
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            cipher.init(Cipher.ENCRYPT_MODE, publicKey);
            return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), publicKey.getModulus().bitLength()));
        }catch(Exception e){
            throw new RuntimeException("加密字符串[" + data + "]时遇到异常", e);
        }
    }

    /**
     * 私钥解密
     * @param data
     * @param privateKey
     * @return
     */

    public static String privateDecrypt(String data, RSAPrivateKey privateKey){
        try{
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            cipher.init(Cipher.DECRYPT_MODE, privateKey);
            return new String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), privateKey.getModulus().bitLength()), CHARSET);
        }catch(Exception e){
            throw new RuntimeException("解密字符串[" + data + "]时遇到异常", e);
        }
    }

    /**
     * 私钥加密
     * @param data
     * @param privateKey
     * @return
     */

    public static String privateEncrypt(String data, RSAPrivateKey privateKey){
        try{
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            cipher.init(Cipher.ENCRYPT_MODE, privateKey);
            return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), privateKey.getModulus().bitLength()));
        }catch(Exception e){
            throw new RuntimeException("加密字符串[" + data + "]时遇到异常", e);
        }
    }

    /**
     * 公钥解密
     * @param data
     * @param publicKey
     * @return
     */

    public static String publicDecrypt(String data, RSAPublicKey publicKey){
        try{
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            cipher.init(Cipher.DECRYPT_MODE, publicKey);
            return new String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), publicKey.getModulus().bitLength()), CHARSET);
        }catch(Exception e){
            throw new RuntimeException("解密字符串[" + data + "]时遇到异常", e);
        }
    }

    private static byte[] rsaSplitCodec(Cipher cipher, int opmode, byte[] datas, int keySize){
        int maxBlock = 0;
        if(opmode == Cipher.DECRYPT_MODE){
            maxBlock = keySize / 8;
        }else{
            maxBlock = keySize / 8 - 11;
        }
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] buff;
        int i = 0;
        try{
            while(datas.length > offSet){
                if(datas.length-offSet > maxBlock){
                    buff = cipher.doFinal(datas, offSet, maxBlock);
                }else{
                    buff = cipher.doFinal(datas, offSet, datas.length-offSet);
                }
                out.write(buff, 0, buff.length);
                i++;
                offSet = i * maxBlock;
            }
        }catch(Exception e){
            throw new RuntimeException("加解密阀值为["+maxBlock+"]的数据时发生异常", e);
        }
        byte[] resultDatas = out.toByteArray();
        IOUtils.closeQuietly(out);
        return resultDatas;
    }

    public static void main (String[] args) throws Exception {
        Map<String, String> keyMap = RSAUtils.createKeys(1024);
        String  publicKey = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCNMitb95Ah6VwBDErE-YsCTfGlWwhv0BACy-lTQV4UxF9mMddNaO7zfOdgNHfplTt76Fe2-i-JVgznsxxzSVAHU1cSM7_9gLEzUJKWa2b--crsioLD0-rSUpnN5ycxQGr90Uhg9fq8lqgRqYKeE-E1eS0qHFN903v5Xoiq722p4QIDAQAB";//keyMap.get("publicKey");
        String  privateKey= "MIICdwIBADANBgkqhkiG9w0BAQEFAASCAmEwggJdAgEAAoGBAI0yK1v3kCHpXAEMSsT5iwJN8aVbCG_QEALL6VNBXhTEX2Yx101o7vN852A0d-mVO3voV7b6L4lWDOezHHNJUAdTVxIzv_2AsTNQkpZrZv75yuyKgsPT6tJSmc3nJzFAav3RSGD1-ryWqBGpgp4T4TV5LSocU33Te_leiKrvbanhAgMBAAECgYAmxGGXTK-sP_Bc8U0OLB34sgHpDseQO6ZJvkb_7vCv7wLqgkDFJkyFWgQFLCLIZYsBiFedC7BFmvTMISdsl_J6x5ujkuRVTcHp3gAQA7UxO6_58fLt-FQveKUJV88HEtUM1RfgoXZn6KfaGWToQROlgrApqEnIGjJe4a_uTTmHKQJBAM_fteQ7Lfxf7sBcJpYl4MlnHXlcM0DJ9bzlqwwAK2RlL5rhCrFC3nw-5SF5HbyJcrErdJY-ai6LD7Be9BjLZfcCQQCt4pYtqPG-4wOh-AmEFirlOdDq5WgJ1gCRM2Helw_ZShI-auXMqAcXFcsPF_X_l6GvQaPgO3vmWZRYnm6w9pjnAkBwHmVo2FKRUNzhe9KEIaIAf1FyZ7xtMYENhYKgUmcVG0515vNxcHO35-SGDWFwk2H9FUco0jlLKU4o_s4BoZM5AkEAmfsECE0KPoKjbePK8Xf75l9rfQdHOSaT_ADnUwislTu9qh5ZfwDwvmWjGquaQQtSt3LGHsQuNM7wygUKepT00wJBAJ-O8d0ELdtKP1_ZTb32gUQE6KECW_aPZVaIgm-aX8ORquzapVg8aWdf9vdnEvv3EaZiisZr1nkxF6RywhtV8Fw";//keyMap.get("privateKey");
        System.out.println("公钥: \n\r" + publicKey);
        System.out.println("私钥： \n\r" + privateKey);

        System.out.println("公钥加密——私钥解密");
        String str = "{\"transaction\":\n" +
                "    {\"transaction_num\":\"A0011712200881\",\"transaction_time\":\"2018-03-06 12:00:00\",\"store_no\":\"1\",\"total_amount\":\"1000\",\"fapiao_info\":{\"purchaser_name\":\"个人\",\"taxpayer_no\":\"\",\"address\":\"上海嘉定区0221\",\"email\":\"1204728512@qq.com\",\"tel\":\"021-5836757\",\"account\":\"62267559854412638\",\"bank\":\"招商银行\",\"mobile\":\"15026705343\",\"detail_type\":\"1\"},\"details\":[{\"item_code\":\"2001040016\",\"item_disamount\":\"800\",\"item_amount\":\"1000\",\"item_quantity\":\"10\",\"item_orderWeight\":\"0\"}],\"payments\":[{\"payment_quantity\":\"121\",\"payment_amount\":\"800\",\"payment_code\":\"HGZF2\"}]}\n" +
                "}\n";
        System.out.println("\r明文：\r\n" + str);
        System.out.println("\r明文大小：\r\n" + str.getBytes().length);
        String encodedData = RSAUtils.privateEncrypt(str, RSAUtils.getPrivateKey(privateKey));
        System.out.println("密文：\r\n" + encodedData);
        String decodedData = RSAUtils.publicDecrypt(encodedData, RSAUtils.getPublicKey(publicKey));
        System.out.println("解密后文字: \r\n" + decodedData);


    }

}
